The present invention relates to an image forming apparatus, and more particularly to improvement of a cleaner for removing toner remaining on the surface of an image bearing body after transfer of a toner image.
Conventionally, in an image forming apparatus such as an electronic photography copying machine, a cleaner having a cleaning blade has been used to remove developing agent not transferred but remaining on the surface of an image bearing body, as disclosed in Jpn. Pat. Appln. KOKOKU Publication No. 63-23552.
Further, there is well known an image forming apparatus which is provided with a magnet member for forcibly attracting waste toner remaining on the image bearing body scraped by a cleaning blade. As a method for removing toner from the roller-shaped magnet member, a method in which a scraper-like toner scraping member is disposed to be in contact with the magnet roller and a method in which a portion of a belt-like sheet member located near the image bearing body brought into contact with the magnet, the end portion of the sheet is separated from magnetic body so as to remove toner have been known.
The remaining toner kept on the surface of the image bearing body in the cleaner by the cleaning blade comes to have a higher packing density compared to ordinary toner if accumulated thereon. Therefore, if the packing density of the accumulated remaining toner increases extremely, a cleaning limit of the cleaning blade is exceeded so that a cleaning fault occurs. Alternatively, a blade edge is damaged by an increase of load so that the aging is accelerated. As a result, the cleaning limit value is lowered thereby leading to such cleaning fault.
Conventionally, to reduce this toner accumulating quantity, a paddle-like rotating body or roll-like magnet is provided to relax the toner pressure. However, because if such a member is provided, the toner scraping member comes into a contact with a rotating roller or paddle, flip sound or friction noise occurs or unnecessary vibration occurs.
Further, because the elastic sheet-like toner separating member vibrates in an enclosed space of the cleaner, gas in the cleaner is discharged out thereof thereby leading to dissipation of toner. Further, the scraping member or paddle or magnet is worn during a copy service life so that removal of toner becomes unequal. As a result, toner collection is partially made difficult so that the cleaning fault is generated.